diff --git a/lib/chess/auth/user.ex b/lib/chess/auth/user.ex
index 546bd82..00d7ca7 100644
--- a/lib/chess/auth/user.ex
+++ b/lib/chess/auth/user.ex
@@ -4,7 +4,6 @@ defmodule Chess.Auth.User do
   use Ecto.Schema
   import Ecto.Changeset
   alias Comeonin.Argon2
-  alias Chess.Repo
 
   schema "users" do
     field :password, :string, virtual: true
@@ -19,7 +18,7 @@ defmodule Chess.Auth.User do
     struct
     |> cast(params, [:username, :password])
     |> validate_required([:username, :password])
-    |> unsafe_validate_unique(:username, Repo)
+    |> unique_constraint(:username)
     |> hash_password()
   end
 
diff --git a/priv/repo/migrations/20180202195257_add_unique_constraint_on_username.exs b/priv/repo/migrations/20180202195257_add_unique_constraint_on_username.exs
new file mode 100644
index 0000000..1b7094c
--- /dev/null
+++ b/priv/repo/migrations/20180202195257_add_unique_constraint_on_username.exs
@@ -0,0 +1,7 @@
+defmodule Chess.Repo.Migrations.AddUniqueConstraintOnUsername do
+  use Ecto.Migration
+
+  def change do
+    create unique_index(:users, [:username])
+  end
+end
diff --git a/test/chess/auth/user_test.exs b/test/chess/auth/user_test.exs
index ea65a3d..594a372 100644
--- a/test/chess/auth/user_test.exs
+++ b/test/chess/auth/user_test.exs
@@ -1,8 +1,11 @@
 defmodule Chess.UserTest do
   use Chess.DataCase
 
+  import Chess.Factory, only: [create_user: 1]
+
   describe "user" do
     alias Chess.Auth.User
+    alias Chess.Repo
 
     @valid_attrs %{username: "zelda", password: "password"}
     @invalid_attrs %{}
@@ -21,15 +24,9 @@ defmodule Chess.UserTest do
       create_user("zelda")
 
       changeset = User.changeset(%User{}, @valid_attrs)
-      refute changeset.valid?
-    end
+      {:error, changeset} = Repo.insert(changeset)
 
-    defp create_user(username) do
-      changeset = User.changeset(
-        %User{},
-        %{username: username, password: "password"}
-      )
-      Repo.insert!(changeset)
+      refute changeset.valid?
     end
   end
 end
diff --git a/test/features/games_test.exs b/test/features/games_test.exs
index 2773872..c14f455 100644
--- a/test/features/games_test.exs
+++ b/test/features/games_test.exs
@@ -2,7 +2,7 @@ defmodule Chess.GamesTest do
   use ChessWeb.FeatureCase
 
   import Wallaby.Query, only: [css: 1, css: 2, button: 1, text_field: 1]
-  import Chess.Factory, only: [create_user: 0]
+  import Chess.Factory, only: [create_user: 2]
 
   test "visit homepage", %{session: session} do
     session
@@ -13,6 +13,7 @@ defmodule Chess.GamesTest do
   test "can create a new game", %{session: session} do
     session
     |> login()
+    |> take_screenshot()
     |> create_game()
     |> assert_has(css(".board"))
   end
@@ -34,7 +35,7 @@ defmodule Chess.GamesTest do
   end
 
   defp login(session) do
-    create_user()
+    create_user("link@hyrule.kingdom", "ilovezelda")
 
     session
     |> visit("/session/new")
diff --git a/test/features/session_test.exs b/test/features/session_test.exs
index 8fa73fe..6a24850 100644
--- a/test/features/session_test.exs
+++ b/test/features/session_test.exs
@@ -2,10 +2,10 @@ defmodule Chess.SessionTest do
   use ChessWeb.FeatureCase
 
   import Wallaby.Query, only: [text_field: 1, link: 1, button: 1]
-  import Chess.Factory, only: [create_user: 0]
+  import Chess.Factory, only: [create_user: 2]
 
   test "user cannot log in with incorrect username", %{session: session} do
-    create_user()
+    create_user("link@hyrule.kingdom", "ilovezelda")
 
     session
     |> visit("/")
@@ -18,7 +18,7 @@ defmodule Chess.SessionTest do
   end
 
   test "user cannot log in with incorrect password", %{session: session} do
-    create_user()
+    create_user("link@hyrule.kingdom", "ilovezelda")
 
     session
     |> visit("/")
@@ -31,7 +31,7 @@ defmodule Chess.SessionTest do
   end
 
   test "user can log in with correct details", %{session: session} do
-    create_user()
+    create_user("link@hyrule.kingdom", "ilovezelda")
 
     session
     |> visit("/")
@@ -46,7 +46,7 @@ defmodule Chess.SessionTest do
   end
 
   test "user can log out", %{session: session} do
-    create_user()
+    create_user("link@hyrule.kingdom", "ilovezelda")
 
     session
     |> visit("/")
diff --git a/test/support/factory.ex b/test/support/factory.ex
index 1ca19af..5389c5a 100644
--- a/test/support/factory.ex
+++ b/test/support/factory.ex
@@ -2,10 +2,10 @@ defmodule Chess.Factory do
   alias Chess.Auth.User
   alias Chess.Repo
 
-  def create_user do
+  def create_user(username \\ "zelda", password \\ "password") do
     User.changeset(
       %User{},
-      %{username: "link@hyrule.kingdom", password: "ilovezelda"}
+      %{username: username, password: password}
     )
     |> Repo.insert!
   end